***** NOT A TEACHER *****
Good morning, Unpakwon:
I have just asked "Professor Google," and if I understood her (!) correctly, it is not the name of a magazine.
The word "note" may refer to a so-called "Teaching Note," which -- I assume -- is a fancy term for an article on how
to teach something. Maybe Mr. Ghemawat's "Note" gave advice to how to teach "creating competitive advantage."
P.S. I apologize if I am wrong. But when I saw you mention the word "magazine," I just had to join this thread, for I love journalism. I think that if it were a magazine title, it would read "Harvard Business School Notes."